Automatic piloting system



Dec. 8, 1936. M. WALLACE AUTOMATIC PILOTING SYSTEM Filed July 29, 1930 6 Sheets-Sheet l INVENTOR- M 90015440, B Y

'ATTORN Dec. 8; 1936.

M. WALLACE AUTOMATIC PILOTING SYSTEM Filed July 29, 1930 6 Sheets-Sheet 2 ekxcuiki 2.

M5 INVENTOR.

QRa/ud Qf/affaxw BY 5 ha? d ATTORNF.

Dec. 8, 1936. M. WALLACE AUTOMATIC PILOTING SYSTEM Filed July 29, 1930 6 Sheets-Sheet 3 Dec. 8, 1936.

M. WALLACE AUTOMATIC PILOTING SYSTEM Filed July 29, 1930 6 Sheets-Sheet 4 INVENTOR. 911mm! QF/afifacw, BY

ATTORNEY Dec. 8, 1936. M. WALLACE 2,063,534

AUTOMATIC PILOTING SYSTEM Filed July 29, 1930 6 Sheets-Sheet 5 IN V EN TOR. Dita 1rd ll/0.66am,

BY 6 7 d ATTORN Y Dec. 8, 1936. M. WALLACE AUTOMATIC PILOTING SYSTEM Filed July 29, 1930 6 Sheets-Sheet 6 INVENTOR. 90%

' A TTORNE n d rmh Patented Dec. 8, 1936 umrso smr s PATENT OFFICE 2,063,534 7 m? JZ ZIK ZJFZLT 1: 3E...

one-third N. Y.

to Edward L. Corbett, New York,

Application July 29, 1930, Serial No. 471,588

9 Claims. '(01. 250-11) 7 My invention relates broadly to piloting systems and more particularly to a system for automatically indicating to the pilot of a navigable vessel the path of his approach to a port.

5 One of the objects of my invention is to provide automatic means for indicating to a pilot the course of travel to a definite point and automatically informing the pilot of the position of the navigable vessel with respect to the port.

Another object of my invention is to provide automatic means which may be located at a port and automatic. means which may be carried aboard a navigable vessel and automatically cooperative for indicating to the pilot on the navi- 15 gable vessel the position of the vessel with respect to the port for aiding the pilot in bringing the vessel to port.

Still another object of my invention is to provide amethod of navigating a vessel with respect to a particular port where means are provided for informing the pilot at all times as to the position of the. vessel with respect to the port which is the destination of the vessel.

Other and further objects of my invention reside in a method of and apparatus for guiding mobile bodies to a designation according to a path which may be visually indicated to the pilot on the mobile body, all of which will be pointed out more fully in the specification hereinafter following byreference to the accompanying drawings, in which:

Figure 1 designates diagrammatically a transmitter circuit carried aboard aircraft for the transmission of signals according to a multiplicity of automatic receiving stations located at an airport or landing field; Fig. 2 diagrammatically shows an aircraft equipped with a transmittingantenna for radiating signals to the automatic receiving station at the airport or landing 40 stations; Fig. 3 is a schematic view illustratin the landing field and obstacles surrounding the field which must be avoided by aircraft in effecting a landing; Fig. 4, is a schematic view showing the arrangement of the automatically ro- 45 tatable loop antenna in each of the two automatic receiving stations which are located at remote positions of the landing field illustrated in Fig. 3; Fig. 5 is a theoretical view showing the relationship of the loop antenna; Fig. 6 dia- 50 grammatically shows the receiving circuits located at remote points on the landing field of Fig. 3; "Fig. 7 shows the land line circuits which are employed ln'recording the operation of the automatic receiving stations for controlling the operation of a transmitter designated at the airport or landing field; Fig. 8 is a plan view the coordinating means at the landing field by which the automatic receiving apparatus controls the operation of the transmitter at the landing field; Fig. 9 diagrammatically shows the transmitting circuit located at the landing field and the control channels by which the apparatus of Fig. 8 controls the transmission of signaling energy to the approaching aircraft; Fig. 10 diagrammatically illustrates the arrangement of re- 10 ceivlng circuit aboard the aircraft and shows the arrangement of ,the mechanism which indicates the path of movement of the aircraft with respect to the airport or the landing field; Figs. 11 and 12 show cross-sectional and plan views respec- 15 tivelyof one form of indicating apparatus which may be carried aboard the aircraft for indicat-. ing to the pilot the position of the aircraft with respect to the position of the landing field; and Fig. 13 shows a modified form of transmission control for the transmission of signaling energy from the landing field, directly controlled by the operation of the automatic receiving stations without the interposition of the land line circuits and control apparatus illustrated in Figs. 7 and 8.

My invention contemplates an indicator which may be carried aboard a navigable vessel and which will at all times inform the pilot as to the position of the vessel with respect to a port. I have illustrated my invention in connection with the navigation of aircraft but it will be understood that my invention is also applicable to the navigation oi vessels at sea for automatically indicating to the pilot the direction of port and the position of the vessel with respect to the port. The circuits of my invention are so arranged that the course of --travel of a vessel or aircraft to any port or landing field may be indicated.

In carrying out the principles of my invention, it is necessary that the ports or landing field be 40 accurately surveyed and charted. The characteristics of each port or landing field must be accurately reproduced on a small size replica consisting of a plate insertable into a carrier mounted before the pilot. The replica of the port or 5 landing field before the pilot shows all of the obstacles which must be avoided in bringing the vessel to port and indicates the safest course to be followed in bringing the vessel to port. A pilot in approaching a certain port or landing o field must insert in the carrier before him the plate bearing in replica the characteristics and outline of that port or landing field. By the operation of the automatic circuits of my invention a tracing stylus or a spot of light appears on the designating the position of the navigable vessel with respect to parts of the port vessel in bringing the vessel to-iport. The ooordination of the several circuits involved in the automatic system may be briefly s as including a transmitter carried aboard the navigable vessel which radiates energy non-directionally in all directions, which energy ispicked up by receiving stations located at widely separated pointswith respect to the landing-fielder port. The receiving stations serve to automatically orient apair of movable arms which intersect. at a point which is relatively movable according, to the direction of the incoming signalenergy picked up by each of the receiving stations from the aircraft. The movable arms change in position according to the change in position of the aircraft approaching the landing field. A pair of independent arms are also provided, intersecting at a point coincident with the point of intersection of the aforesaid movable arms. These last mentioned arms serve to control the movement of contactors over a pair of resistors in variable amounts according to the position of the transmitting aircraft. The resistors are located in separate tone control circuits of a transmitter which is erected adjacent the landing field, and as the resistors are variably controlled, diiferent amounts of energy of particular tone frequency will be radiated from the transmitter on'the same carrier frequency. On the aircraft, 1 provide areoeivlng circuit adapted to receive the carrier frequency from the landing field, with separate tone channels responsive to the tone frequencies emitted from the transmitter. Each tone channel controls the angular movement of an electromagnetic member to which is secured a moving armor plate pivoted in positions adjacent the replica of the landing field at points geographically correspondingto the position of the automatic receiving stations on the landing field. This cut enables the movable arms to be shifted to a position where the intersection thereof designates the position of the'alrcraft with respect to the parts of the landing field that the aircraft is approaching. In lieu of movable arms with a stylus. at

the end thereof for tracing the course of the aircraft I may employ movable sectors having radially disposed slots therein, the intersection of which provides-a path for light which may be directed through the plate members upon the chart to indicate the position of aircraft with respect to the parts of the landing field by means of a moving spot of light. In lieu of the system of movable arms for interlinhng the automatic receiving stations with the transmit-- ting station at the landing field, I may directly coordinate the automatic receiving stations with the tone frequency control means of the transmitter for variably emitting different quantities .of modulated energy from the transmitter.

' Referring to the drawings in more detail, :referencecharacter I designates the antenna carried uponaircraft as illustrated in Fig. .2,

' the' antenna }I being connected to a transmitter circuitlncluding an oscillator as and a tuned cir- .cuit 4 connected to counterpoise 2' on the aircraft and adapted to emit carrier frequency which is picked up by the automatic receiving stations I and 6' located on the landing field I illustrated lay 28.

in Fig. 3. The automatic receiving stations 5 and 6 are very accurately located with respect to the parts of the landing field in such manner that a replica or chart of the landing field with pivotal points for a system of moving arms located adjacent the replica or chart on the aircraft in precisely the same geographical positions as are occupied by the automatic receiving stations 5 and 6. On the landing field I; I have indicated generally obstacles such as the hangar 8, the tank 9, the overhead telegraph, telephone and power lines It. and trees Illa. The runways .jqrthe aircraft are designated at i I. All of these and other natural obstacles such as mountains adjacent the landing field mustbe reproduced in detail on the chart I25 which is mounted in carrier l2|a. before the pilot. Each automatic receiving station indicated at 5 and 6 comprising elements which have been shown schematically in Fig. 4 as including a vertically rotatable shaftifi journalled in a suitable frame structure i6, loop antenna I2 is disposed in one plane and loop antenna. M disposed in a plane normal thereto. Leads are taken from loop l2 through suitable collector rings and brushes to the connections designated at an.

Connections are taken from loop It through suitn'ected at Mal. The rotatable shaft I5 is provided with a gear il in the end thereof which is driven automatically by means of motor It to a position where the resultant 26 indicated in the die in Fig. 5, which is the bisector of the angle between loops [2 and M, effectively extends in the direction of the approaching aircraft.

At each automatic receiving station I provide means for automatically orienting the loops as shown indetail in Fig. 6. The loop I! conmeets to the radio frequency amplifier channel illustratedat 2!, the terminals l2a being connected to the input of the amplifier, the input able collector rings and brushes to leads -concircuit being permanently tuned to a selected frequency by means of condenser 28. The output of radio frequency amplifier 2i connects to theinput circuit of detector 22 permanently tuned to the frequency transmitted from the aircraft by means of condenser 24. The loop It w whichis mounted upon rotatable shaft I5 is coninput circuit of which is permanently tuned by means of condenser 32 to the frequency of the energy transmitted from the aircraft transmitter. The detectors 21 and 30 connect to a common power supply circuit and in the output circuits there are arranged separate audio frequency transformer systems 21 and 33. The transformer system 21 connects through tuned circuit 26 to the rectifier tube 25, the output circuit of which includes the winding-31 of re- The transformer system 33 connects to tuned circuit 34 and 'to the input of.rectifier tube 36. the. output circuit of which connects, through winding 31 ofrelay 28. Relay 28 in-. cludes a tongue 28:: to which coil l'l is con-' nected and contacts 28b and 28c with which tongue 20a, connects according to whether or not the amplitude of the received signaling energypredominates either in loop I! oriloop N. The contacts 28b and lie control the circuit from a source of power 38 to elects itor ll so that these electromagnets are alternatively energized according to whether or not the signaling energy in loop circuit I2 exceeds the amplitude of the signaling energy in loop circuit I4 or vice versa. when the signaling,energy in the two amplifier channels is equal, relay tongue 2811; is balanced, and contacts 28b and 28c are both open so that solenoids 39 and 48 are both deenergized, thereby opening sets of contacts 4| and 42 and deenergizing .driving moto'f l8 by cutting ofi the supply of powerirom source 44 to field 43. Under this condition shaft l5 remains stationary. However, should the signaling energy in loop circuit I2 exceed the amplitude ofthe signaling energy in loop circuit l4,

an unbalance will occur tending to remove relay V I5 carries a contacting arm 41 which moves over theresistance 46. Leads 460. and 41a extend from the ends of resistance 46 and from the contact arm 41' respectively. These leads may extend a substantial distance by land line to a central position on the landing field as indicated in Fig; '7. The two automatic receiving stations at remote positions on the landing field have been'reproduced diagrammatically at 5 and 6. The land wires'which extend from each automatic receiving station connect to relay circuits indicated at 48 and 68. The leads 46a. extend to the. ends of a potentiometer 49. The leads 660 from the resistor 66 at the automatic receiving station 5 extend to the ends of the potentiometer 53. A central combining apparatus 54 is provided with a plane member on which movable arms 5|. and 52 are pivotally mounted at 5|a. and 52a. Arm 5| has an extension contact 58 which moves over potentiometer 49. Arm 52 has an extension contact N! which moves over potentiometer 58. The'arm 5| with its extension contact 58 journaled at 5|a. is positively 'drivenby means of motor 56. Field winding 51 of motor v56 is connected to source of potential v 58 through switching relays 63--64 which are controlled by solenoids 59 and 60. Solenoids 59 and 60 are selectively energized from source of potential 6| through contact system 62c-62b of relay 48. When relay tongue 62a, is moved to contact 62c, solenoid 59 is energized actuating motor 56 in one direction while under the condition where contact arm 62 moves to contact 62b, solenoid 68 is energized thereby closing contact 64 and reversing the direction of movement of motor 66. This operation is similar to the j reversal of the armature and field connections '41 on potentiometer 46 there is a corresponding position for contactor arm 50 on potentiometer 49. It will therefore be apparent that movement of the automatic receiving station loops will bring about an angular displacement of contactor 41 and a corresponding displacement ofcontactor 56. Arm 6| which is connected to the contactor arm '58 will have a movement corresponding to the movement of contactor 50. The arrangement of the automatic-receiving station 5 is identical with the arrangement of the automatic receiving station 6; That is, the resistor 66 connects to the ends of potentiometer 58 through leads 66a and across source of potential 18. The movable winding 12 connects between the contactor I3 and the contactor arm 61 through leads 61a in the same manner that winding 62 of relay 48 connects between contactor 41 on resistor 46 and contactor arm 50 on potentiometer 49 through lead 410,. The relay 68has tongue 12a arrangedto move with winding 12. Contacts 12b and 12c are arranged on opposite sides of the relay tongue 12a. Solenoids 18 and 86 connect with source of potential tongue 12a. Solenoids 19 and 88 control sets of contacts 88 and 84 for eifecting a reversal oi movement of motor 16 by reversing the direc tion of the field 11 with respect to the armature 16 from the potential source 58. Motor 16 positively drives the contact arm I3 and angularly movable arm 52 about the pivot 52a as a center. When the automatic receiving station 5 shifts contactor. arm '61 along resistor 66, a corresponding movement of contact arm I3 is brought about by operation of driving motor 16 under control of relays 68 It will be understood that relays 68 and 48 have normal midpositions at which time the driving motors 56 and 16 are not in operation. Displacement of the contactor 41 or 61 by means of the automatic receiving stations eiTect an unbalance .in the land line circuits, thereby causing relays 48 and 68 to shift to a position tending to restore a balance and bringing about the required operation of the motors 56 and 16 operating contactor arms 58 and i3 rendering portions of the potentiometers 49 and 53 effective in the landing line circuits of such order as will tend to restore a balance of the land line circuits thereby shifting relays 48 and 68 and bringing about the accompanying operation or stopping of motors 56 and- 16. The movable arm 52 establishes sliding connection with movable arm 5| intersecting as indicated at 55. A consideration of the coordinated movement of the two automatic receiving stations will show that the point of intersection 55 varies according to the position of the transmitting aircraft with respect to the landing field. In order that this variable factor may be reproduced aboard the. aircraft, a transmitting station located at the landing field is variably controlled according to the movement of the point of intersection at 55. This is broughtabout by an arrangement of angularly movable arms 85 and 86 pivoted at 85a. and 86a and having contactor extensions 81 and 88 establishing connection with potentiometers 15 and 65 respectively.

a In Fig. 9, I have shown in detail the arrangement of potentiometers 65 and 15 in the modulation circuits of the transmitter. The contactor arms 81 and 88 are illustrated in Fig. 9 as variably including selected portions of the potentiometers 65 and 15 in the modulation control circuit;

Fig. 8 will render the operation of the control means of my invention much clearer in that it will be seen that the angularly movable arms 5| and 52 are each longitudinally slotted as indicated at SR; and 521) so that as the angular relation of the arms vary under control of the positive driving connections with motors 56 and 16 respectively, the intersecting connection 55 I may slide longitudinally along the angularly movable members 5I and 52. The transmitter control potentiometers 65 and I5 have their corresponding angularly movablearms 8.6 and 85 slotted at 861) and 85b respectively so that the point of intersection 55 will shift arms 86 and 85 in'a similar manner for correspondingly varying the position of contactors 88 and 81 on potenti ometers 65 and I5. I p

In the transmitter system illustrated in Fig. 9 separate tone channels are provided constituted by generators 89 and 90 developing the potentials E. and E, respectively. 7 Across these generators the potentiometers 65 and I5 are shunted. Selected quantities of the energy from the tuned channels may be derived from potentiometers 65 and I5 by the movement of the contactors 88 and Blunder control of the angularly movable members 86 'and 35 respectively. The separate tone channels are coupled to' the oscillator I through independent amplifiers 92 and 94 and through commonamplifier 98. The amplifier the transmitter; the two sound channels connected through transformer 91 with amplifier 98 to oscillator. I00. The oscillatorl00 is coupled to antenna IN and ground I02 for the radiation of energy modulated according to two different tone frequencies. The apparatus on the aircraft which cooperates with the transmitting circuit of Fig. 9. is shown diagrammatically in Fig. 10, the antenna counterpoise system being illustrated at I03--I04 connected to the input cir- -cuit I of the radio frequency amplification system including tubes I06, I01 and I03, the

output of which connects to the detector tube J09, all of the circuits of. the several amplilief-stages andthe detector stage being tuned I through the unicontrol tuning arrangement H0.

former being tuned as represented at H4 and The output of the detector. includes independent tone channels connected to tunedtransformers III and I I2, the secondary circuit of each trans- -I I5. The tone channel which connects to transformer III includes amplifier II3 with a'frequency selector circuit .II5 therein for excluding all frequencies except that tone frequency towhich the tone channel is selective. The output ofthe amplifier II3 connects through transformer IIG to the rectifier circuit III to which -there is connected the pivotally'mounted winding- 9 forming part of the electrodynamic "system including field magnet 9a. The coil II9 connects through. a filter circuit H8 between a mid-tap connection on a potentiometer I3I which bridges the cathode of rectifier tube II'I and the mid-tap connection IIGa. in the secondary winding of transformer H6. The oathode of rectifier tube III is heated from the source of potential which connects across .po-

tentiometer I3I and which is used for heating the cathodes of the other tubes in the receiving circuit! The movable coil H9 is pivoted at 120a and connects to the angularly movable arm I20 which is adapted to sweep'over the replica or chart I2I which shows the various parts of the aircraft landing field.

with arm I20 at the point I22.

transmitter I.

The second tone channel includes transformer II2 tuned to one of the modulating tone frequencies, the secondary of the transformer being tuned by means of circuit I26 to respond to the second of the two modulating tone frequencies, the circuit I26 being connected to the input of the amplifier tube I25 to the filter I21 which excludes all tone frequencies except that tone frequency which is desired for operating the electrodynamic apparatus at the receiver. The output of amplifier I25 connects through transformer I28 with the circuit-of rectifier tube I29. A filter circuit I30 connects between a midpoint in the cathode resistor I32 and a midpoint I28a in the secondary of the transformer 128, the output of the filter. connecting to moving coil I24 of the electrod'ynamic device I24a. The coil" I24 is pivoted at I23a. and is secured to angularly movable arm I23 which intersects The point I22 may travel over the entire area of the chart or replica I2I indicating to the pilot the exact position of the aircraft with respect to the parts of landing field. The point I22 may be in the nature of a stylus for drawing a line on the chart I2| showing the course of the aircraft. In lieu of the stylus and angularly movable arms, I may pivotally mount sets of sectors 'I33 and I34 in positions behind the chart I2I as illustrated in Figs. 11 and 12. In this arrangement the pivotal mounting means illustrated at I20a and I23a are each located as are the cor-- respondingly numbered means in Fig. in such relation to the'chart I2I that these pivot points bear the exact geographical relation to the parts of the landing field in replica as do the automatic receiving stations 5 and 6 on the landing field of Fig.3.

In Figs. 11 and 12, the movable sectors I33 and I34 are slotted radially at, I33o and I34a intersecting at I35 in such manner as to provide a path for light rays from the light source I36 directed by the reflector I3'I to the rear of the chart IZI. in the holder I2Ia and is translucent in character so that the light spot at I35 will appear for securing the required results.

In lieu of the coordination board 54 as shown in Fig. 7 on the landing field I may employ the direct control method illustrated -i n Fig. 13 wherein the automatic receiving stations illustrated. at S and 6 have the rotatable shafts I5 and I33 directly connected to conductor arms I40 movable over resistors I4! and I42 where resistor I4I connects in shunt .w'lth tone frequency generator 90 while resistor I42 connects The chart I2I is removably carriedin shunt with'tone frequency indicator 9|: The

effective potentialfrom generator 90 is supplied over circuit I43 to control the transmitter I44. The effective potential from tone frequency generator as is supplied over circuit I45 to control The amounts of energy supplied to the tone modulation circuits of the transmitter I44 are variably controlled in accordance with themovement of contacts I40. and I39 of the rotatable loop receiving stations for automatically controlling the transmission of energy ta the approaching aircraft. The transmitted signaling energy is modulated at the two difaoeaesc i'erent audio notes obtained from generators 89 and 90 varying in amplitude according to the position of the 'contactors actuated by the automatic receiving stations.

In both the combining board line wire system of Fig. 7 and the direct control transmitting *system of Fig. 13, I depend upon a plurally modulated carrier frequency where the carrier is modulated at :dlfierent tone frequencies, the amplitude ofintensity of each tone frequency varying continuously and correspondingly controlling the movement of the angularly movable members at the receiver for indicating the position of the aircraft and the course of approach thereof to the landing field. In all instances where I have mentioned the movement of the aircraft with respect to the landing field, it will be understood that the system is equally applicable in guiding ships into a harbor or port,

'where the moving stylus at the receiver or spot of light at the receiver indicates the location or the ship with respect to the harbor or port.

The system of my invention may be standardized so that each port or landing field may supply charts in replica to aircraft flying between cities of which the said landing field is one of the terminal points. By standardizing the geographical location of the pivoting points 851:. and 86a with relation to each airport in the same compass position with respect to the parts in replica, all of the landing fields are coordinated in a standardized system, so that it is only necessary for the pilot to change the chart or replica as he approaches the particular-landing field which the chart represents in .order that the moving spot of light or stylus may guide him to a safe landing position on the held. The chart or replica of the landing field may be in the shape of an aerial photograph with all the obstacles represented, so that the pilot is fully informed regarding the character of the country surrounding the landing fieldand is warned of the dangers which may impair safe landing. The pivotal points'of the idler arms 85a and 864 at the transmitting point, correspond to the position Hfla. and me at the receiving point on the aircraft. The position of the automatic receiving stations can be any suitable one, but oi course,

the appearance of the board represented by Fig. 8 would be modified according to each local condition. In other words, the position of the automatic receiving stations automatically orient idlers in relation to, the field similitude is always the same. driven arms may be at any convenient point.

If, however, the automatic receiving'stations are situated in the geographical points represented by a and 86a, then,'and only then, the disposition shown in Fig. 13 becomes possible.

The automatic operation of the receiving stations is such that it is unnecessary to provide an operator at the receiving stations b and a. Power is supplied to the circuits of the receiver from suitable generators of from a power line system and'except for a replacement of tubes, no other attention to the automatic receiving circuits is normally required. The loops-in the to a position where the resultant points toward the plane, thereby bringing about the required movement of the contactor arm on the associated potentiometer for either direct control or "'the plurally modulated transmitter or for the the balanced land line circuit and the control or v of the plurally modulated transmitter actuation tioned pair of arms,

The position '0! the motor gheil'ough the combining board on the landing d.

In the claims I have used the term landing port synonomously with the term flying course" and I do not mean that the pilot actually lands at such position. My invention is equally applicable to the navigation of aircraft over a flying course wherein the pilot places different contour charts or replica maps of the flying course in the carrier before him by which the light spot or visual indicating device represents the safest flyin course to the pilot. The entire flying course may be navigated by the system of my invention as a fiying course may be erected by arranging a continuous chain of adjacent landing fields equipped with the system of my invention for indicating the safest course to the pilot. Nothing prevents the use of one of the directional receiving stations for several adjacent portions of the flying course.

While I have described my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than are imposed by the scope of, the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In a system for indicating the path of movement of a vehicle, a combin n board comprising in combination with a'plane area, a pair of pivctally mounted arms adapted to angularly shift in intersecting relationship, independent means for driving each of said arms, a pair of pivotally mounted similarly arranged arms dis- .posed in intersecting relation with respect to each other and with respect to the aoremen= an adjustable potentiometer controlled by eachoi said last mentioned pair of arms, and a common c nnection for all of said arms at the position of gintersecting relationship thereoi whereby angular movement imparted to said first mentioned pair of arms is similarly transferred to said second mentioned pair of arms.

2. In a system for indicating the movement of a mobile body, a combining board comprising in combination with a pair of pivotally mounted arms, each movable over the plane area in intersecting relationship, a potentiometer controlled by each of said arms, independent means for angularly driving each of said a a pair of similarly arranged pivoted arms; a potentiometer controlled by the movement of each of said arms, and means extending through the intersecting portions of all of said arms whereby said first mentioned pair oi arms transmits movement to said second mentioned pair of arms.

3. In an apparatus for transmitting electrical energy in accordance with the movement of a mobile body, the combination of a pair of normally balanced bridge circuits, an angularly movable device operatively controlled by each of said normally balanced bridge circuits, an angularly movable arm driven by each of said movable devices in intersecting relation, a pair of pivotally mounted arms extending in intersecting relationship overlappin the aforesaid arms, a potentiometer device controlled by each of said last mentioned arms, and common means interconnecting said arms in the intersecting positions thereof whereby angular movement imparted to said first mentioned arms it erred to said second mentioned arms gag to the angular movement of said last mentioned pair of arms.

. 4. In a system for transmitting angular motion, a pair of normally balanced bridge circuits, an angular-1y movable device controlled by each of said normally balanced bridge circuits, a pivotally mounted angularlymovable arm connected with each of said angularly movable devices, said arms being angularly movable in intersecting relation over a plane area and having means connected therewith for controlling the balanced relationship of said bridge circuits, :1. pair of similarly mounted pivoted arms arranged in intersecting relationship and overlapping the aforementioned arms, a potentiometer controlled by each of said last mentioned arms, and common means for maintaining all of said arms in intersecting relation continuously throughout the path of .--.-w-= movement of all of said arms.

5. In a system for transmitting angular motion, a pair of bridge circuits, a relay controlled by each of said bridge circuits, a pair of angularly movable devices, circuits individual to each of said arly movable devices controlled by the saidrelays for determining the direction of angular movement oi said angularly movable devices, a pivotally mounted arm driven-by each of said angularly movable devices in intersecting relatiop one with the other, a pair of similarly arranged pivotally mounted arms extending in overlapping intersecting relationship'with re.- spect to said first mentioned arms, and a. potentiometer devicecontrollable by each oi said last mentionedpair of arms.

6. In a system for transmittingangular mo i tion, a pair of bridge circuits, a relay controlled by each or said bridge circuits, apair of anguilerly movable devices, circuits individual to each oi said angularly movable devices controlled by the said relays for determining the direction of angular movement of said angularly movable devices, a. pivotally mounted arm driven by each of said angularly movable devices in intersecting relationship one with the other, a. pair of similarly arrangedpivctally mounted extending in overlapping intersecting relationship with respect to said first mentioned arms, and a variable impedance device controllable by each of said last mentionedarms.

L'In a system for transmitting angular mov tion, a, pair of bridge circuits, a relay controlled by each or said bridge circuits, a pair of angularly movable devices, circuits-individual to each of said; movable devices controlled by the d relays fordetermining the direction ementoi said r r21 ly. movable i. 2,088,584 and the said potentiometers controlled according devices, a pivotally mounted arm driven by each of said angularly movable devices in intersecting relationship one with the other, a pair at similarly arranged pivotally mounted arms extending in overlapping intersecting relationship with respect to said first mentioned arms, balancing means in each ofsaid bridge circuits controllable by the movement of said first mentioned arms,

and variable impedance means correspondingly controllable by the. movement of said last mentioned pair of arms.

8. In a system for transmitting angular motion, a pair of bridge circuits, a relay controlled by each of said bridge circuits, a pair of angularly movable devices, circuits individual to each of said angularly movable devices controlled by the said relays for determining the direction of angular movement of said angularly movable devices, a pivotally mounted arm driven by each of said angularly movable devices in intersecting relationship one with the other, apair of similarly arranged pivotally mounted arms extending in overlapping intersecting relationship with respect to said first mentioned arms, balancing means disposed in each of said bridge circuits, means connected with said first mentioned arms for adjusting said ing means, loop antennae adapted to be oriented to diflerent angular positions for unbalancing each of said bridge circuits and controlling the movement of said angularly movable means for restoring the balance of said bridge circuits, and variable impedance means controlled by the movement of each of said last mentioned air of arms.

. 9. in a system for ansmitting angular motion, a pair of bridge circuits, a relay controlled by each oi said bridge circuits, a pair of angularly movable devices, circuits individual to each of said angularly movable devices controlled by thesaid relays for determining the direction of angular movement of said angularly movable devices, a pivotally mounted arm driven by each of said angularly movable devices in intersecting relationship one with the other, a pair of similarly arranged pivotally mounted arms extending in overlapping intersecting relationship with respect to said firstmentioned arms,loop antennae individual to each of said bridge circuits and adapted to control by the orientation thereof the balance oi each of said bridge circuits, separate balancing means in each of said bridge circuits controlled bythe movement 01 said first mentioned arms, and variable circuit controlling 'means operated by said last mentioned arms for transmitting angular motion imparted by said 

